package demo2;

import java.util.*;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String str1 = in.nextLine();
            func(str1);
        }
    }
    public static void func(String str1) {
        StringBuilder sb = new StringBuilder();
        int index = -1;
        int i = 0;
        while (i < str1.length()) {
            if (index == -1) {
                sb.append(str1.charAt(i));
                index++;
                i++;
            } else {
                if (str1.charAt(i) == sb.charAt(index)) {
                    sb.deleteCharAt(index);
                    index--;
                } else {
                    sb.append(str1.charAt(i));
                    index++;
                }
                i++;
            }
        }
        if (index == -1) {
            System.out.print(0);
        } else {
            System.out.println(sb);
        }
    }
}

















